1. Field of the Invention
The present invention relates to semiconductor devices having a circuit constituted by a thin film transistor (hereinafter, also referred to as a TFT), and a manufacturing method of the semiconductor devices. For example, the present invention relates to electronic devices mounting, a part thereof, an electro-optical device typified by a liquid crystal display panel or a light-emitting display device having an organic light-emitting element.
Note that a semiconductor device in this specification indicates a general device which can function with use of semiconductor characteristics, and the category of the semiconductor devices in this specification includes all types of devices such as electro-optical devices, semiconductor circuits and electronic devices.
2. Description of the Related Art
In recent years, a technique for forming a thin film transistor (TFT) using a thin semiconductor film (the thickness: about several to several hundred nm) formed over a substrate having an insulating surface has been attracted attentions. Thin film transistors have been widely used in electron devices such as ICs or electro-optical devices, and in particular, such thin film transistors have been developed actively as switching elements of image display devices.
The application range of active matrix type display devices which are typical image display devices, has become broad, and high definition, high aperture ratio or high reliability has been required more, with the increase in screen size.
In order to realize a high-performance semiconductor device which can operate at high speed, a structure with a low-electric-resistant wiring material will be more needed.
Reference 1 (Japanese Patent Application Laid-Open No. 2000-188251) describes a technique in which a film is formed over a semiconductor wafer using a device which can discharge a resist solution from a nozzle to have a thin linear shape.